On a new Short-taihd Opossum from Brazil. 441 



skulls of true lofiusi, rangin<>- from Karyatein (^CarrutJiers) 

 to Mohammorali {Loftus)^ before me, and tbree of the Muscat 

 f()rm,# find that tliere are certain cranial differences between 

 the two and would suggest that the latter should be distin- 

 guishedas 



Jacalus loftusi vocator, subsp. n. 



External characters quite as in loftusi, but, tlie specimens 

 being or having been in spirit, the exact tone of colour cannot 

 be observed. 



Skull of about the same size as in loftusi Anteorbital 

 foramina smaller, of more equal breadth above and below, 

 not expanded above as in loftusi ; greatest breadth across 

 the two foramina in four specimens of loftusi 15"8, 16'2, 15*2, 

 and 15*4, in tliree specimens of vooator 14*2, 14'0, and 14"0. 

 Front edge of zygomatic plate outside the foramina more 

 vertical, nearly at right angles (88°, 89°) to the line of the 

 tooth-row, while in lojtasi it slants back considerably (75'', 

 76°). Interparietal smaller, averaging about 4"5 X 5'4 as 

 compared with 5'5 X 7*0 mm. Other characters apparently 

 quite as usual. 



Dimensions of type, measured on the spirit-specimen: — 



Head and body 95 mm.; tail 164 ; hind foot 57 ; ear 21. 



Skull: greatest median length 29"7; greatest diagonal 

 length to back of bulla? 32 ; greatest breadth across face 22'4 ; 

 interorbital breadth 12 ; bimeatal breadth 23'2 ; anteorbital 

 foramen, height 5*4, breadth across the two foramina 14*2 ; 

 upper molar series 4"8. 



Ilah. Coast region near Muscat ; type from Sohar, others 

 from Seeb. 



Type. Adult male in spirit. B.M. no. 0. 5. 22. 3. 

 Presented by Dr. A. S. G. Jayakar. 



Although the two co-types of loftusi (of which 55. 1. 6. 82 

 may now be formally selected as a lectotype) have the 

 zygomatic plate broken away, enough remains to show that 

 the anteorbital foramina are of quite the same shape as iu 

 our series from Karyatein. 



XLIV. — A. new Short-tailed Opossum from Brazil. 

 By Oldfield Thomas. 



(Published by permission of the Trustees of the British Museum.) 



Monodelphis theresa, sp. n. 

 Most nearly allied to M. i/ieringi. 



Size about as in iheringi ; fur similarly short and close, 

 hairs of back about 4 mm. in length. Coloration on the 



